JP3484912B2 - Toner for developing electrostatic latent images - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a toner for developing an electrostatic latent image.
In particular, the present invention relates to a toner for developing an electrostatic latent image used in a digital electrophotographic apparatus.

[0002]

2. Description of the Related Art Conventionally, as an image forming apparatus, an analog system such as a copying machine which forms an electrostatic latent image on a photoconductor by irradiating a document with light from a light source and irradiating the photoconductor with the reflected light. Image forming apparatus is generally used. Further, as a digital image forming apparatus for supplying a developer containing toner to the electrostatic latent image obtained by digital writing to develop the image, a printer or an image reader used for output from a computer terminal is used. A digital copying machine that forms an image based on the read image information, an electrophotographic facsimile, and the like have been put into practical use.

In the digital type image forming apparatus,
An electrostatic latent image is formed in dot units on the photoconductor by digital writing such as irradiation with a light beam, and this latent image is used as a toner image.
The toner image thus obtained is transferred onto a recording medium such as recording paper and fixed to form a recorded image. In this way, the toner used in the digital system is
At the time of transfer and heat fixing, it is required that the dot thickness due to the collapse of the toner is small, that is, the dot reproducibility is excellent. If the dot reproducibility is poor, halftone skipping, image collapse, and the like will occur, resulting in a problem of image quality deterioration.

Further, in recent years, an image forming apparatus equipped with an automatic document feeder and a double-sided copying apparatus has been adopted with the increase in speed and multifunction of the image forming apparatus. When a document is fed or a back side is copied by these devices, the image surface is rubbed by the roller when the paper is fed, and the image quality is deteriorated due to a phenomenon such as bleeding or dirt on the image.

Further, such a toner is also required to be free from image contamination due to an offset phenomenon during heat fixing, that is, to have excellent offset resistance. In order to improve the offset resistance, it is effective to add a release agent such as wax to the toner. However, the wax is released during the production of the toner, and the release wax causes the filler to fill the photoreceptor. There is a problem of mingling or a problem of black spots in which the toner composition adheres to the free wax attached to the photoreceptor as a nucleus.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, and an object thereof is to provide an electrostatic latent image developing toner which solves the problem of image quality deterioration due to rubbing. It is what

It is an object of the present invention to provide a toner for developing an electrostatic latent image having excellent offset resistance.

It is an object of the present invention to provide an electrostatic latent image developing toner which solves the problems of filming and black spots.

A further object of the present invention is to provide a toner for developing an electrostatic latent image which is excellent in dot reproducibility.

[0010]

The present invention provides a toner for developing an electrostatic latent image containing at least a binder resin, a colorant and a wax, the binder resin having an acid value of 5 to 50 KOHmg / g and a softening point of 95 to. 120 ° C and
And a first polyester resin having a glass transition point of 50 to 75 ° C., an acid value of 5 to 50 KOHmg / g, and a softening point of 130 to
The second porosity having a temperature of 160 ° C. and a glass transition point of 50 to 75 ° C.
Use a polyester resin at a weight ratio of 7: 3 to 2: 8
A polypropylene wax is a melt blend of a non-oxidized polypropylene wax and an oxidized polypropylene wax having an acid value of 20 to 70 KOHmg / g, which is produced by using polyethylene wax and polypropylene wax as the wax .
Acid value of 1~20KOHmg / g and a binder resin 1
0.5 to 5 parts by weight with respect to 00 parts by weight,
The melt viscosity of polyethylene wax at 160 ° C is 1
000~8000cps, your softening point of 130~150 ℃
And the addition amount to 100 parts by weight of the binder resin is 0.
1 to 5 parts by weight of the toner for developing an electrostatic latent image.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The toner of the present invention uses a polyester resin having an acid value of 5 to 50 KOHmg / g, preferably 10 to 40 KOHmg / g as a main component of a binder resin. By using the polyester resin having such an acid value, it is possible to improve the dispersibility of polyethylene wax or polypropylene wax described later, suppress the generation of free wax, and solve the problem of photoreceptor filming. When the acid value is less than 5 KOHmg / g, the above-mentioned effects are reduced, and the acid value is 50
If it exceeds KOHmg / g, the stability of the toner charge amount against environmental changes, particularly humidity changes, is impaired.

In the present invention, as the polyester resin, a polyester resin obtained by polycondensing a polyhydric alcohol component and a polycarboxylic acid component can be used.

Among the polyhydric alcohol components, examples of the dihydric alcohol component include polyoxypropylene (2,
2) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (3,3) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-Hydroxyphenyl) propane polyoxyethylene (2,0) -2,2-
Bisphenol A alkylene oxide adduct such as bis (4-hydroxyphenyl) propane, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol , 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, dipropylene glycol, polyethylene glycol, polytetramethylene glycol, bisphenol A, hydrogenated bisphenol A, etc. Is mentioned.

Examples of trihydric or higher alcohol components include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,
2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1,3.
5-trihydroxymethylbenzene etc. are mentioned.

Examples of the divalent carboxylic acid component of the polyvalent carboxylic acid components include, for example, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid. , Succinic acid, adipic acid, sebacic acid, azelaic acid, malonic acid, n-dodecenylsuccinic acid, isododecenylsuccinic acid, n-dodecylsuccinic acid, isododecylsuccinic acid, n-octenylsuccinic acid, isooctenylsuccinic acid, Examples thereof include n-octyl succinic acid, isooctyl succinic acid, and anhydrides or lower alkyl esters of these acids.

Examples of the trivalent or higher carboxylic acid component include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2,5-benzenetricarboxylic acid, 2,
5,7-naphthalene tricarboxylic acid, 1,2,4-naphthalene tricarboxylic acid, 1,2,4-butane tricarboxylic acid, 1,2,5-hexanene tricarboxylic acid, 1,3
-Dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, 1,2,
7,8-octanetetracarboxylic acid, pyromellitic acid,
Examples thereof include empol trimer acids, anhydrides of these acids, and lower alkyl esters.

Further, in the present invention, as the polyester resin, a mixture of a raw material monomer of the polyester resin, a raw material monomer of the vinyl resin, and a monomer which reacts with the raw material monomers of both resins is used, and the polyester is put in the same container. A resin obtained by carrying out a polycondensation reaction for obtaining a resin and a radical polymerization reaction for obtaining a styrene resin in parallel can also be suitably used. The monomer that reacts with the raw material monomers of both resins is, in other words, a monomer that can be used in both the condensation polymerization reaction and the radical polymerization reaction. That is, it is a monomer having a carboxy group capable of polycondensation reaction and a vinyl group capable of radical polymerization reaction, and examples thereof include fumaric acid, maleic acid, acrylic acid and methacrylic acid.

Examples of the raw material monomers for the polyester resin include the above-mentioned polyhydric alcohol component and polyvalent carboxylic acid component.

Examples of raw material monomers for vinyl resins include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, and the like.
Styrene or styrene derivatives such as p-tert-butylstyrene and p-chlorostyrene; ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, isobutylene; methyl methacrylate, n-methacrylic acid
Propyl, isopropyl methacrylate, methacrylate n
-Butyl, isobutyl methacrylate, methacrylic acid t-
Butyl, n-pentyl methacrylate, isopentyl methacrylate, neopentyl methacrylate, methacrylic acid 3
-(Methyl) butyl, hexyl methacrylate, octyl methacrylate, nonyl methacrylate, decyl methacrylate, undecyl methacrylate, dodecyl methacrylate, and other alkyl methacrylate esters; methyl acrylate, n-propyl acrylate, isopropyl acrylate , N-butyl acrylate, isobutyl acrylate, t-butyl acrylate, n-pentyl acrylate, isopentyl acrylate, neopentyl acrylate, 3- (methyl) butyl acrylate, hexyl acrylate, octyl acrylate, acrylic acid Nonyl, decyl acrylate,
Acrylic acid alkyl esters such as undecyl acrylate and dodecyl acrylate; acrylic acid, methacrylic acid,
Unsaturated carboxylic acids such as itaconic acid and maleic acid; acrylonitrile, maleic acid ester, itaconic acid ester, vinyl chloride, vinyl acetate, vinyl benzoate, vinyl methyl ethyl ketone, vinyl hexyl ketone, vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether. Etc. Examples of the polymerization initiator at the time of polymerizing the raw material monomer of the vinyl resin include, for example,
2,2′-azobis (2,4-dimethylvaleronitrile, 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1-carbonitrile),
Azo or diazo polymerization initiators such as 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile,
Examples thereof include peroxide type polymerization initiators such as benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxycarbonate and lauroyl peroxide.

In the present invention, it is preferable to use two kinds of polyester resins having different softening points as the polyester resin in order to improve the fixing property and the offset resistance. That is, the first polyester-based resin having a softening point of 95 to 120 ° C. is used to improve the fixability, and the softening point is 13 to improve the offset resistance.
It is preferable to use a second polyester resin having a temperature of 0 to 160 ° C. In this case, when the softening point of the first polyester resin is lower than 95 ° C, the offset resistance is lowered and the dot reproducibility is lowered, and when it is higher than 120 ° C, the effect of improving the fixing property is insufficient. If the softening point of the second polyester resin is lower than 130 ° C, the effect of improving the offset resistance is insufficient, and if it is higher than 160 ° C, the fixability is deteriorated. From this viewpoint, the softening point of the first polyester resin is more preferably 100 to 115 ° C, and the softening point of the second polyester resin is more preferably 135 to 155 ° C. Also the first
And the glass transition point of the second polyester resin is 50 to
It is desirable that the temperature is 75 ° C, preferably 55 to 70 ° C.
This is because if the glass transition point is low, the heat resistance of the toner becomes insufficient, and if it is too high, the pulverizability at the time of production decreases and the production efficiency decreases.

The first polyester-based resin is a polyester resin obtained by polycondensing the above-mentioned polyhydric alcohol component and polycarboxylic acid component, and in particular, the main component is a bisphenol A alkylene oxide adduct as the polyhydric alcohol component. A polyester resin obtained by using at least one selected from the group consisting of terephthalic acid, fumaric acid, dodecenylsuccinic acid, and benzenetricarboxylic acid as the main component as the polycarboxylic acid component is preferable.

As the second polyester resin,
Using a mixture of a polyester resin raw material monomer, a vinyl resin raw material monomer, and a bireactive monomer that reacts with both resin raw material monomers, a polycondensation reaction to obtain a polyester resin and a vinyl resin can be performed in the same container. The polyester resin obtained by carrying out the radical polymerization reaction in parallel is preferable from the viewpoint of improving the dispersibility of the wax, the toughness of the toner, the fixing property, and the offset resistance. The content of the vinyl resin in the second polyester resin is 5 to
It is 40% by weight, preferably 10 to 35% by weight. When the content of the vinyl resin is less than 5% by weight, the dispersibility of the polyethylene wax is lowered and the fixing strength of the toner is lowered. If it exceeds 40% by weight, the dispersibility of the polypropylene wax, the offset resistance and the toughness of the toner, the negative charge level, and the like are likely to occur.

The weight ratio of the first polyester resin to the second polyester resin is 7: 3 to 2: 8, preferably 6 :.
It is preferably set to 4 to 3: 7. By using the first polyester resin and the second polyester resin in such a range, the toner has a small spread due to crushing at the time of fixing and is excellent in dot reproducibility. Excellent fixability can be secured even in a high-speed image forming apparatus. Further, it is possible to maintain excellent dot reproducibility during double-sided image formation (when passing through the fixing device twice). When the proportion of the first polyester resin is less than the above range, the low temperature fixability becomes insufficient and a wide fixability cannot be secured. If the proportion of the second polyester resin is less than the above range, the offset resistance tends to deteriorate and the toner crushing during fixing tends to become large, resulting in deterioration of dot reproducibility.

The softening point of the resin is the flow tester (C
FT-500: manufactured by Shimadzu Corporation, using a die hole (diameter: 1 mm, length: 1 mm), pressure of 20 kg / cm ² , and heating rate of 6 ° C./min, a sample of 1 cm ² is melted and flown out. 1 / height of the outflow start point to the outflow end point
The temperature corresponding to 2 was defined as the softening point. The glass transition point was measured using a differential scanning calorimeter (DSC-200: manufactured by Seiko Denshi KK), using alumina as a reference, and a 10 mg sample at a temperature rising rate of 10 ° C./min between 20 and 120 ° C. The shoulder value of the main endothermic peak was taken as the glass transition point. Acid value is 10mg sample, 50ml toluene
Dissolved in water and pre-standardized with 0.1% mixed indicator of bromthymol blue and phenol red N / 1
Titrate with 0 potassium hydroxide / alcohol solution to N / 10
It is a value calculated from the consumption amount of potassium hydroxide / alcohol solution.

Since the toner of the present invention contains the polyethylene wax, the problem of deterioration of image quality due to rubbing (smear property) is solved. As a polyethylene wax, the melt viscosity at 160 ° C. is 1000 to 800.
It is preferable to use a polyethylene wax having 0 cps and a softening point of 130 to 150 ° C. That is, by using a polyethylene wax having the above-mentioned melt viscosity and softening point, the coefficient of friction of the fixed image surface is reduced to improve the smearing property, and polyethylene wax particles released from the toner at the time of production are mixed in the toner. This can be reduced and the problem of photoconductor filming can be solved. The melt viscosity of the wax was measured with a Brookfield viscometer.

Binder resin 1 of polyethylene wax
The addition amount to 100 parts by weight is 0.1 to 5 parts by weight, preferably 0.3 to 3 parts by weight. If the addition amount is less than 0.1 parts by weight, the above-mentioned effect of the polyethylene wax addition becomes insufficient.

Further, the toner of the present invention comprises a non-oxidizing polypropylene wax and an acid value of 20 to 70 KOHmg /.
g of polypropylene wax, which is a melt blend of oxidized polypropylene wax, is added to solve the problem of offset phenomenon without causing new problems such as filming. In this case, the content of the oxidized propylene wax in the polypropylene wax is adjusted to 3 to 15% by weight, and finally the acid value of the propylene wax is adjusted to 1 to 20%.
Adjust to KOH mg / g, preferably 3 to 15 KOH mg / g. Such polypropylene wax has improved dispersibility in the polyester resin having the above-mentioned acid value, and free wax is less likely to be generated. Acid value is 1
If it is less than KOHmg / g, the effect of improving the dispersibility becomes insufficient, and if it is more than 20KOHmg / g, the offset resistance decreases. Furthermore, as polypropylene wax,
It is preferable to use a melt viscosity at 160 ° C. of 50 to 300 cps and a softening point of 130 to 160 ° C. because it is particularly effective in eliminating the high temperature offset phenomenon. The polypropylene wax obtained by the melt blending has a volume average particle diameter of 10 to 20 μm when pulverized.
It is preferable to use the toner prepared as described above in the production of toner.

The amount of polypropylene wax added to 100 parts by weight of the binder resin is 0.5 to 5 parts by weight, preferably 1 to 4.5 parts by weight. If the addition amount is less than 0.5 part by weight, the above-mentioned effect of the polypropylene wax addition becomes insufficient. Furthermore, it is desirable that the total content of polypropylene wax and polyethylene wax is 5 parts by weight or less, preferably 4 parts by weight or less with respect to 100 parts by weight of the binder resin. This is because the fluidity of toner intermediate particles (coarsely pulverized particles, finely pulverized particles, etc.) at the production stage is deteriorated as well as the toner obtained when the total addition amount exceeds 5 parts by weight, and thus the inter-production devices It is not preferable because these particles tend to adhere to the walls of transportation equipment and the like, which leads to a decrease in production efficiency.

If desired, a negative charge control agent, magnetic powder, etc. may be added to the toner of the present invention.

Examples of negative charge control agents include chromium complex salt type azo dyes S-32, 33, 34, 35, 37, 3
8, 40 (manufactured by Orient Chemical Industry Co., Ltd.), Eisenspirone Black TRH, BHH (manufactured by Hodogaya Chemical Co., Ltd.), Kayaset Black T-22,004 (manufactured by Nippon Kayaku Co., Ltd.), copper phthalocyanine dye S-39 ( Orient Chemical Industry Co., Ltd.), salicylic acid chromium complex salt E-81, 82 (Orient Chemical Industry Co., Ltd.), zinc salicylate complex salt E-84 (Orient Chemical Industry Co., Ltd.), salicylic acid aluminum complex salt E.
-86 (manufactured by Orient Chemical Industry Co., Ltd.), calixarene compound E89 (manufactured by Orient Chemical Industry Co., Ltd.), benzylic acid boron complex salt and the like can be mentioned.

As the magnetic powder, for example, fine particles of a known magnetic material such as ferrite, magnetite and iron can be used, and may be added from the viewpoint of preventing toner scattering, but the addition amount is the binder resin 100. It is 10 parts by weight or less, preferably 8 parts by weight or less with respect to parts by weight. Addition amount is 1
If the amount exceeds 0 parts by weight, the magnetic force of the developer bearing member (built-in magnet roller) against the toner becomes strong and the developability deteriorates.

Further, the toner of the present invention may be treated by externally adding inorganic fine particles to the surface thereof. The inorganic fine particles may be added by mechanically mixing the toner and the inorganic fine particles. Examples of the inorganic particles include silica particles, titanium dioxide particles, alumina particles, magnesium fluoride particles, silicon carbide particles, boron carbide particles, titanium carbide particles, zirconium carbide particles, boron nitride particles, titanium nitride particles, zirconium nitride particles, magnetite particles. The fine particles of molybdenum disulfide, the fine particles of barium titanate, the fine particles of strontium titanate, the fine particles of aluminum stearate, the fine particles of magnesium stearate, the fine particles of zinc stearate and the like can be used alone or in combination of two or more kinds. Preferably, silica fine particles and titanium dioxide fine particles are used in combination and externally added. The amount of the inorganic fine particles added is 0.05 to 2% by weight, preferably 0.1 to 1% by weight, based on the toner. By using such an added amount,
The fluidity can be improved without impairing the environmental stability of the developer. In addition, as the inorganic fine particles, it is preferable to use those that have been subjected to a hydrophobic treatment from the viewpoint of improving environmental stability, and as the hydrophobic treatment agent, silane coupling agents, titanium coupling agents, higher fatty acids, silicone oils, etc. Can be used. BE as the above-mentioned inorganic fine particles
It is preferable to use a T specific surface area of 80 to 180 m ² / g. By using the inorganic fine particles having such a BET specific surface area, it is possible to reduce the fluidity to 200 with respect to a small particle diameter toner having an average particle diameter of 5 to 9 μm.
Compared with the case of using inorganic fine particles of m ² / g or more, the addition amount can be increased and the fluidity can be improved without impairing the environmental stability. Further, not only the fluidity can be improved, but also the transferability when the toner image formed on the surface of the photoconductor is transferred onto a recording medium such as recording paper can be improved, and the dot reproducibility can be improved. it can.

Further, the toner of the present invention can be used as a two-component developer used together with a carrier or a one-component developer not containing a carrier. As the carrier used for the two-component developer, a conventionally known carrier can be used.

[0034]

EXAMPLES The present invention will be described below with reference to examples, but the invention is not limited thereto.

(Production Example of Polyester Resin L1) Polyoxypropylene (2,2) -2,2-bis (was added to a glass four-necked flask equipped with a thermometer, a stirrer, a downflow condenser and a nitrogen inlet tube. 4-hydroxyphenyl) propane, polyoxyethylene (2,2)-
2,2-bis (4-hydroxyphenyl) propane, isododecenyl succinic anhydride, terephthalic acid and fumaric acid were adjusted to a weight ratio of 82: 77: 16: 32: 30 and added with dibutyltin oxide as a polymerization initiator.
220 in a mantle heater under a nitrogen atmosphere
The reaction was carried out with stirring at ° C. The obtained polyester resin L1 had a softening point of 110 ° C., a glass transition point of 60 ° C. and an acid value of 17.5 KOHmg / g.

(Production Example of Polyester Resin L2) Polyoxypropylene (2,2) -2,2-bis (4) was placed in a glass four-necked flask equipped with a thermometer, a stirrer, a downflow condenser and a nitrogen inlet tube. -Hydroxyphenyl) propane, polyoxyethylene (2,2)-
2,2-bis (4-hydroxyphenyl) propane, terephthalic acid and 1,2,4-benzenetricarboxylic anhydride were adjusted to a weight ratio of 73: 30: 45: 3 and added together with dibutyltin oxide as a polymerization initiator. . This was reacted in a mantle heater under a nitrogen atmosphere while stirring at 220 ° C. Obtained polyester resin L2
Had a softening point of 111.5 ° C., a glass transition point of 70 ° C. and an acid value of 19.3 KOHmg / g.

(Production Example of Polyester Resin H1) Styrene and 2-ethylhexyl acrylate were adjusted to a weight ratio of 17: 3.2, and put in a dropping funnel together with digyl peroxide as a polymerization initiator. On the other hand, polyoxypropylene (2,2) -2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene were placed in a glass four-necked flask equipped with a thermometer, a stirrer, a downflow condenser and a nitrogen inlet tube. (2,2) -2,2
-Bis (4-hydroxyphenyl) propane, isododecenyl succinic anhydride, terephthalic acid, 1,2,4-benzenetricarboxylic anhydride and acrylic acid in a weight ratio of 4
It was adjusted to 2: 11: 11: 11: 8: 1 and added together with the polymerization initiator dibutyltin oxide. This was stirred at 135 ° C. in a mantle heater under a nitrogen atmosphere, styrene or the like was added dropwise from a dropping funnel, and the temperature was raised to react at 230 ° C. The obtained polyester resin H1 had a softening point of 150 ° C., a glass transition point of 62 ° C. and an acid value of 24.5 KOHmg / g.

(Production Example of Polyester Resin H2) Polyoxypropylene (2,2) -2,2-bis (was added to a glass four-necked flask equipped with a thermometer, a stirrer, a downflow condenser and a nitrogen inlet tube. 4-hydroxyphenyl) propane, polyoxyethylene (2,2)-
The weight ratio of 2,2-bis (4-hydroxyphenyl) propane, isododecenyl succinic anhydride, terephthalic acid and 1,2,4-benzenetricarboxylic anhydride is 73: 3.
It was adjusted to 0: 18: 25: 3 and added together with a polymerization initiator dibutyltin oxide. This was reacted in a mantle heater under a nitrogen atmosphere while stirring at 220 ° C. The softening point of the obtained polyester resin H2 is 15
4 ℃, glass transition point 64 ℃, acid value 20.4KOHm
It was g / g.

(Melt-blended polypropylene wax A
Example of production) Non-oxidizing polypropylene wax (Viscole 550P; manufactured by Sanyo Chemical Industry Co., Ltd.) with an acid value of 0 KOHmg / g and an acid value of 5
A weight ratio of 2 KOHmg / g of oxidized polypropylene wax (Umex 1010; manufactured by Sanyo Chemical Industry Co., Ltd.)
After mixing at 2: 8, melt-kneading, cooling and pulverizing to obtain an acid value of 4.0.
KOH mg / g, melt viscosity at 160 ° C 205 cp
A melt-blended polypropylene wax A having a softening point of 150 ° C. was obtained.

(Melted Blend Polypropylene Wax B
Production Example) In the same manner as in the production example of melt-blended polypropylene wax A, the acid value was 6.8 KOHmg / g and 160 ° C in the same manner except that the weight ratio of the non-oxidized polypropylene wax and the oxidized polypropylene wax was 87:13. A melt-blended polypropylene wax B having a melt viscosity of 210 cps and a softening point of 150 ° C. was obtained.

Example 1 40 parts by weight of polyester resin L1, 60 parts by weight of polyester resin H1 and polyethylene wax (800
P; manufactured by Mitsui Petrochemical Co., Ltd .; melt viscosity at 160 ° C. 5400 cps; softening point 140 ° C.) 1 part by weight, melt blended polypropylene wax A 3 parts by weight, acidic carbon black (Mogal L; manufactured by Cabot Co .; pH 2.
5; 8 parts by weight of average primary particle size 24 nm) and 1.5 parts by weight of a negative charge control agent represented by the following formula;

[0042]

[Chemical 1]

Was thoroughly mixed with a Henschel mixer, melt-kneaded with a twin-screw extrusion kneader, cooled, then coarsely pulverized with a hammer mill and finely pulverized with a jet pulverizer, and then classified to have a volume average particle diameter of 7.5 μm. Toner particles were obtained.

The toner particles have a BET specific surface area of 140 m.
0.4% by weight of ² / g of hydrophobic silica fine particles (H2000: manufactured by Hoechst) and BET specific surface area of 110 m ² / g
0.2 wt% of the hydrophobic titanium dioxide fine particles (STT30A: manufactured by Titanium Industry Co., Ltd.) was added and mixed to obtain a toner.

Example 2 In Example 1, the addition amount of the polyester resin L1 was 60 parts by weight and the addition amount of the polyester resin H1 was 4 parts.
Change to 0 parts by weight, polyethylene wax polyethylene wax 400P (Mitsui Petrochemical Co., Ltd .; 1
Melt viscosity at 60 ° C. 1600 cps; Softening point 136
C.) 1.5 parts by weight, the melt-blended polypropylene wax A was changed to the melt-blended polypropylene wax B, and the negative charge control agent was changed to Bontron S-34 (manufactured by Orient Chemical Industry Co., Ltd.) 3 parts by weight. A toner was obtained in the same manner except that the above was performed.

(Example 3) In Example 1, 50 parts by weight of the polyester resin L2 was used in place of the polyester resin L1, 50 parts by weight of the polyester resin H2 was used in place of the polyester resin H1, and The negative charge control agent is Bontron S-34
A toner was obtained in the same manner except that the amount was changed to 3 parts by weight (manufactured by Orient Chemical Industry Co., Ltd.).

Example 4 A toner was obtained in the same manner as in Example 1, except that the amount of polyethylene wax added was changed to 0.5 part by weight.

Comparative Example 1 In Example 1, the melt-blended polypropylene wax A was replaced with polypropylene wax (Umex 101).
0; manufactured by Sanyo Chemical Industry; acid value 52 KOHmg / g, 16
Melt viscosity at 0 ° C. 7000 cps; Softening point 145
℃) and changed the negative charge control agent to Bontron S-34
A toner was obtained in the same manner except that the amount was changed to 3 parts by weight (manufactured by Orient Chemical Industry Co., Ltd.).

Comparative Example 2 A toner was prepared in the same manner as in Example 1 except that polyethylene wax was not added and the negative charge control agent was changed to 3 parts by weight of Bontron S-34 (manufactured by Orient Chemical Industry Co., Ltd.). Got

Comparative Example 3 In Example 1, the amount of polyethylene wax added was 2
A toner was obtained in the same manner except that the amount was changed to parts by weight, polypropylene wax was not added, and the negative charge control agent was changed to 3 parts by weight of Bontron S-34 (manufactured by Orient Chemical Industry Co., Ltd.).

Comparative Example 4 Polyester resins L1 and H1 in Example 1
In place of styrene-acrylic resin (MX-9500;
A toner was obtained in the same manner except that 100 parts by weight of Sanyo Chemical Industry Co., Ltd.) was used and the negative charge control agent was changed to 3 parts by weight of Bontron S-34 (manufactured by Orient Chemical Industry Co., Ltd.).

(Comparative Example 5) In Comparative Example 1, polypropylene wax was used as Viscole 550P (manufactured by Sanyo Chemical Industry Co .; acid value 0 KOHmg /
g, melt viscosity at 160 ° C. 200 cps; softening point 1
A toner was obtained in the same manner except that the temperature was changed to 50 ° C.

The obtained toners and the digital copying machine (Di
30; carrier manufactured by Minolta Co., Ltd.) was mixed in a weight ratio of toner: carrier = 5: 95 to adjust the developer, and the following evaluations were performed. The results are shown in Table 1.

(Offset resistance) The digital copying machine Di in which the set temperature of the fixing device is variably modified
30 is used to form a solid image (2 × 5 cm) with an image density (ID) = 1.4, the obtained image is visually confirmed, and the temperature at which the offset occurs is defined as the high temperature offset generation temperature. did. High temperature offset generation temperature is 240
Those having a temperature of ℃ or more were evaluated as ◯, those having a temperature of 220 ° C or more and less than 240 ° C were evaluated as Δ, and those having a temperature of less than 220 ° C were evaluated as x.

(Smear resistance (rubbing stain resistance)) A solid image (2 × 5 cm) having an image density (ID) = 1.4 was formed using Di30, and a white paper was placed on the obtained image to obtain 200 g. The blank paper was reciprocated three times by applying the load. The stains on the image at this time are visually evaluated. When no stain is found at all, it is ◯, when a little stain is found but there is no practical problem, it is at Δ, and there is stain and there is a practical problem. The thing was marked as x.

(Filming and Black Spot) Durability evaluation of 120,000 sheets was performed using Di30, and the presence or absence of filming was visually observed on the surface of the photoconductor thereafter. It was confirmed whether or not the toner became matte and that toner components were fixed (black spots). The case where neither filming nor black spot occurred was evaluated as ◯, and the case where either filming or black spot occurred was evaluated as x.

(Dot Reproducibility) A 2 × 2 dot (400 dpi) halftone image was formed using a modified Di30 machine in which the fixing roller temperature was set to 180 ° C. The diameter of each halftone dot image of the obtained halftone dot image is measured using an image analysis device, data of about 80 to 100 halftone dots is obtained, and the maximum diameter value Dmax is obtained and ranked as follows. went. Rank 10 when Dmax is less than 185 μm,
Ranks 9 and 18 from 185 μm to less than 187.5 μm
Ranks between 190 μm and 7.5 μm and less than 190 μm
Or more and less than 192.5 μm in rank 7, 192.5 μm or more and less than 195 μm in rank 6, 195 μm or more in 197.
Ranks below 5 μm were evaluated as ranks 5, ranks 9 and 10 were evaluated as ◯, ranks 7 and 8 were evaluated as Δ, and ranks 6 and below were evaluated as x.

[0058]

[Table 1]

[0059]

According to the present invention, it is possible to provide an electrostatic latent image developing toner which solves the problem of image quality deterioration due to rubbing.

Further, according to the present invention, a toner for developing an electrostatic latent image having excellent offset resistance can be provided.

Further, according to the present invention, it is possible to provide a toner for developing an electrostatic latent image which solves the problems of filming and black spots.

Further, according to the present invention, it is possible to provide a toner for developing an electrostatic latent image which is excellent in dot reproducibility.

Front page continued (72) Inventor Hiroyuki Fukuda 2-3-13 Azuchi-cho, Chuo-ku, Osaka, Osaka, Osaka International Building Minolta Co., Ltd. (56) Reference JP-A-8-166686 (JP, A) JP-A 8-114946 (JP, A) JP-A-6-208244 (JP, A) JP-A-5-224457 (JP, A) JP-A-4-124676 (JP, A) JP-A-1-284863 (JP, A) A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03G 9/08

Claims (3)

(57) [Claims] 1. An electrostatic latent image developing toner containing at least a binder resin, a colorant and a wax, wherein the binder resin has an acid value of 5 to 50 KOHmg /
g , softening point 95 to 120 ° C. and glass transition point 50 to 7
First polyester resin having a temperature of 5 ° C and an acid value of 5 to 50K
OHmg / g, softening point 130-160 ° C and glass rolling
Weigh the second polyester resin whose transition point is 50-75 ° C.
It is used in a quantity ratio of 7: 3 to 2: 8, and is manufactured using polyethylene wax and polypropylene wax as waxes. The polypropylene wax is a non-oxidized polypropylene wax and an acid value of 20 to 70 KOHm.
It is a melt blend of g / g oxidized polypropylene wax, and the acid value of the melt blend is 1 to 20 KOH.
mg / g and addition to 100 parts by weight of binder resin
The amount is 0.5 to 5 parts by weight , and the melt viscosity of polyethylene wax at 160 ° C. is 1000 to 8000 cp.
s , a softening point of 130 to 150 ° C. and a binder resin 1
An electrostatic latent image developing toner amount added is characterized by 0.1 to 5 parts by weight der Rukoto for 00 parts by weight. 2. The toner for electrostatic latent image development according to claim 1, wherein the content of the oxidized propylene wax in the melt blend is 3 to 15% by weight. 3. The polypropylene wax at 160 ° C.
Has a melt viscosity of 50 to 300 cps and a softening point of 13
The toner for developing an electrostatic latent image according to claim 1, which has a temperature of 0 to 160 ° C.